The author Hanif Kureishi accused the BBC of censorship last night, after it dropped a radio broadcast of his short story describing the work of a cameraman who films the executions of western captives in Iraq.

Radio 4 cancelled a reading of Weddings and Beheadings, one of five nominations for the National Short Story prize due to be broadcast this week, after concluding the timing "would not be right" following unconfirmed reports that kidnapped BBC Gaza correspondent Alan Johnston had been killed by a jihadist group.

Kureishi, whose work includes The Buddha of Surburbia, Intimacy and the screenplay for the film My Beautiful Launderette, said he was angry at the decision, which he described as a result of "stupid thinking" on the part of BBC executives.

"It seems to me that as a journalist, he would be against censorship," he said of Johnston, who has been missing for more than a month and for whom fears intensified on Sunday when a previously unknown group, the Palestinian Brigades of Monotheism and Holy War, claimed to have killed him.

Kureishi said: "There are journalists and newspapers in peril all the time around the world. We support them by supporting freedom of speech rather than by censoring ourselves."

The short story, nominated for the £15,000 prize run by Prospect magazine, describes the work of a camerman who has been forced to take on work filming the executions that have become a feature of recent kidnaps in the Middle East. The BBC said it would have pulled the programme regardless of whether or not Johnston worked for the BBC or was a journalist.

"An important criterion when deciding whether to transmit a particular story on a difficult subject is the timing of the transmission . We do not now feel that it would be right to broadcast at the moment. We will review this on a regular basis," it said. But Kureishi said it was important to uphold the principle of free speech: "It's not trivial or silly. It's an attempt to say something. It all seems rather arbitrary."

Channel 4 recently rescheduled The Mark of Cain, a drama about the abuse of Iraqi prisoners by British soldiers, in case it had a bearing on the treatment of the British sailors held at that time by Iran.